In 2015, the LHCb collaboration observed two pentaquark or pentaquark molecule candidates \(P_c(4380)\)  and \(P_c(4450)\)  in the \(J/\psi p\)  invariant mass spectrum in the \(\Lambda _b^0\rightarrow J/\psi K^- p\)  decays [1]}. In 2019, also in the \( J/\psi p\)  invariant mass spectrum, the LHCb collaboration observed a new narrow pentaquark or pentaquark molecule candidate \(P_c(4312)\)  and confirmed the old structure \(P_c(4450)\) , which consists of two narrow overlapping peaks \(P_c(4440)\)  and \(P_c(4457)\)  [2]}.
There have been several possible interpretations for the quark structures of the \(P_c(4312)\) , \(P_c(4440)\)  and \(P_c(4457)\) , such as the pentaquark molecular states [3]}, [4]}, [5]}, [6]}, [7]}, [8]}, [9]}, [10]}, [11]}, [12]}, [13]}, [14]}, [15]}, [16]}, [17]}, [18]}, [19]}, [20]}, [21]}, [22]}, [23]}, [24]}, [25]}, [26]}, [27]}, [28]}, [29]}, [30]},
compact diquark-diquark-antiquark type pentaquark states or diquark-triquark type pentaquark states [31]}, [32]}, [33]}, [34]}, [35]}, [36]}, [37]}, [38]}, [39]}, [40]}, [41]}, [42]}, [43]}, [44]}, [45]}, [46]}, [47]}, color-octet-color-octet type pentaquark states [48]}, hadrocharmonium pentaquark states [49]}, etc.
